Infrared endoscopic system for bleeding-point detection after flushing with indocyanine green solution (with videos)

BackgroundInfrared endoscopy is used to visualize vessels in the GI tract. By applying this system, we developed a new method to visualize a bleeding point during endoscopic resection.ObjectiveThis study aimed to evaluate the ability of infrared endoscopy to detect a bleeding point during endoscopic resection and to elucidate the mechanism required for clear visualization of a bleeding point by in vitro color analysis.DesignObservational case series.SettingA cancer-referral center.Patients and InterventionsA total of 10 bleeding sites were observed during endoscopic resection of upper-GI cancers by infrared endoscopy after flushing with indocyanine green (ICG) solution (0.125 mg/mL water).Main Outcome MeasurementsDetection of bleeding points.ResultsBleeding points were identified in all bleeding sites by infrared endoscopic viewing. Bleeding points were displayed in white, whereas, an ulcer bed was in blue and pooled blood was a blue-to-gray color. By in vitro color analysis, blood was white, blood twice diluted with ICG solution was dark blue, and blood 4-times diluted with ICG solution was light blue on infrared endoscopic views. Color differences with blood dilution were more obvious in an infrared endoscopic view compared with a conventional endoscopic view. Blood thickness, movement, and clotting did not influence the color differences.LimitationsUncontrolled study.ConclusionsWe reported a flushing method by which we could detect all bleeding points during endoscopic resection. Clear visualization of bleeding points comes from differences in blood and ICG concentration between spurting and pooled blood.